1. Field
Some example embodiments relate to electrical energy generators, and more particularly to hybrid electrical energy generators that can transform sunlight and/or mechanical vibration energy into electrical energy.
2. Description of the Related Art
Solar cells may transform solar energy into electrical energy. Solar cells may include a p-type semiconductor material and an n-type semiconductor material. When light is directed onto a solar cell, solar cells may generate electrons and holes. The generated electrons and holes may move to an n-type electrode and a p-type electrode respectively, thereby generating electrical energy. Researchers are researching whether using nanostructures, such as nanowires, may improve the efficiency of solar cells.
A hybrid electrical energy generator may transform sunlight or mechanical vibration into electrical energy according to a surrounding environment. A hybrid electrical energy generator may have a structure in which a photovoltaic element and a piezoelectric element are integrated together, and thus a photovoltaic effect and a piezoelectric effect may occur together or separately. In a hybrid electrical energy generator, electrical energy can be generated by using two different energy generation methods: a photovoltaic method and a piezoelectric method. However, the electrode contact characteristics desired for the photovoltaic method are different from those desired for the piezoelectric method. For example, ohmic contact characteristics may be desirable for the photovoltaic method and Schottky contact characteristics may be desirable for the piezoelectric method.